A bikini-clad Gisele Bundchen declined to wear helmets while riding an ATV with 13-month-old daughter Vivian in Costa Rica on Jan. 13.Credit: x17online.com

Maybe not the best mode of transportation? Gisele Bundchen was spotted riding an ATV without a helmet in Costa Rica on Monday, Jan. 13 -- while carrying 13-month-old daughter Vivian. In the x17 photos, the bikini-clad supermodel drove with one hand while also holding her daughter, who was strapped in a baby carrier, against her chest.

After they arrived at the beach, Bundchen, 33, took Vivian for a dip in the water. The stunning model showed off her slim and toned physique in a skimpy bikini, while her daughter went naked and diaper-free.

Gisele Bundchen took daughter Vivian for a dip in Costa Rica on Jan. 14.Credit: x17Online.com

This isn't the first time Bundchen has driven an ATV in the Central American paradise with a baby on board. The mom of two was photographed back in March going for a ride with Vivian and husbandTom Bradyin Costa Rica.